Holding the hand of a loved one to comfort them really does help reduce pain, a US study has shown.

Dr Pavel Goldstein, a postdoctoral pain researcher in the Cognitive and Affective Neuroscience Lab at the University of Colorado Boulder was inspired to conduct the research after witnessing the birth of his daughter four years ago.

He said: "My wife was in pain, and all I could think was, 'What can I do to help her?' I reached for her hand and it seemed to help.

"I wanted to test it out in the lab: Can one really decrease pain with touch, and if so, how?"

His team found that when an empathetic partner holds the hand of a woman in pain, their heart and respiratory rates sync and her pain dissipates.

Dr Goldstein said: "The more empathetic the partner, the stronger the analgesic effect and the higher the synchronisation between the two when they are touching."

Researchers examined 22 couples as part of the study into "interpersonal synchronisation" where individuals begin to physiologically mirror the people they are with.

The phenomenon is seen everyday when people sync their footsteps with the person they're walking with or adjust their posture to mirror a friend's during conversation.

Dr Goldstein's study is the first to explore interpersonal synchronisation in the context of pain and touch.

He hope it can inform the discussion as health care providers seek opioid-free pain relief options.

The 22 heterosexual couples, between the age of 23 and 32, were put them through a series of tests aimed at mimicking a delivery-room scenario.

The couples either sat together, not touching; sat together holding hands; or sat in separate rooms and repeated all three scenarios as the woman was subjected to a mild heat pain on her forearm for two minutes.

The study found when the couples were allowed to hold hands they synced and the pain decreased.

Dr Goldstein said: "It appears that pain totally interrupts this interpersonal synchronisation between couples. Touch brings it backs."

His previous research found he more empathy the man showed for the woman the more her pain subsided during touch and the more physiologically synchronised they were, the less pain she felt.

He said: ""It could be that touch is a tool for communicating empathy, resulting in an analgesic, or pain-killing, effect."

The team say more research is needed to discover how a partner's touch eases pain.

The results of the study was published in the journal Scientific Reports last week.

Recent studies also show that when people watch an emotional film or sing together, their heart rates and respiratory rhythms synchronise.

Researcher has also shown leaders and followers have a good rapport, their brainwaves fall into a similar pattern and when romantic couples are simply in each other's presence, their cardiorespiratory and brainwave patterns sync up.